A new kind of gaming craze is causing a stir online and stealing a march on the big console companies. Mini-programs known as “social games” live on the home pages of social networking sites such as Facebook and MySpace and in the past few months have enjoyed a phenomenal rise in popularity. They are free to play — all you need is an internet connection and an ordinary computer or iPhone.

Some of the games can be played in minutes while others, such as Scrabble, can go on for days. Gamers can play on the move, and swap scores with people on their contacts lists, sparking fierce one-upmanship that has helped the games to gain popularity.

Specialist social games makers such as Playfish, Zynga and SGN boast more than 100m players worldwide. Zynga claims to have 45m active players of its games, which are offered through Facebook, MySpace and Bebo. It is behind Texas Hold’em, the most popular game on Facebook with more than 13m active players last month. Texas Hold’em is closely followed by Mafia Wars, another Zynga game, with more than 12m players, then Pet Society, made by Playfish, with more than 11m.

Mobile phones are the new frontier for social gaming, with Playfish and SGN recently making their games available for iPhones. SGN says more than 12m people have downloaded its iPhone games.

To get some idea of the rapid take-up of social gaming, bear in mind that even the Fifa 09 football title, one of the world’s biggest-selling and most established console games, has sold only 10m copies worldwide since its release last autumn. No wonder the big console makers are worried.

Microsoft, which makes the Xbox console, has announced a tie-up with Facebook and Twitter that will allow Xbox 360 users to link to either site via their console and share scores or post messages with online friends. Some console aficionados remain sniffy, but Electronic Arts, a developer and publisher of console games such as Need for Speed and The Sims, is already working on games for Facebook.

The economic downturn has given social games a boost — people are now cash-poor and time-rich — but cost is only part of the attraction. They may be simple in comparison with console games, but their appeal is that users can play more easily against their real friends. They can then exchange scores and brag about their performance.

“Consumers are looking for more experiences to connect with their friends,” says Mark Pincus, chief executive of Zynga. “We see our games as playgrounds for personalities. Our estimate is that by 2012 there will be 500m people involved in social games.”

Playfish’s Restaurant City — a game that allows players to set up fantasy restaurants and swap recipes with friends — now has more than 5.2m active players on Facebook. Its appeal lies less in the competitive swapping of scores than in co-operation and the sharing of ideas. “A social game is a game where the primary emotional reason you play is not what’s going on in the screen itself, but how that game affects you and your real-world friends,” says Kristian Segerstrale, chief executive of Playfish, which is based in London. “It’s like the reasons you play card or board games with your family, or football in the park. It’s about competition, co-operation and expression.”

True, nobody’s yet throwing out their PS3 because they’re playing Pet Society on Facebook, but Segerstrale thinks the future of gaming looks more like his company’s titles than the expensive games on the PS3 or Xbox 360. “The console industry has navigated itself into a place where it’s not sustainable as it stands,” he says. “In the current economic situation, social gaming is a more compelling model than asking the consumer to pay £40 or so for a new game.”

Pet Society

A stylised cross between The Sims, Animal Crossing and Nintendogs, this has you creating a pet and pimping out its house, while socialising and competing against friends.

Restaurant City

Run a restaurant, researching recipes, swapping ingredients with other players and hiring your Facebook friends to work as waiters, chefs and cleaners.

Mafia Wars

Suitably godfather-bothering strategy game in which you recruit friends and work your way up the mafia ranks to become the don.

iBowl

In this bowling game you swing your iPhone to bowl. Social features such as posting scores to Facebook impress the most.

Farm Town

Design, grow and run a farm, sending gifts to your friends and generally living the good life. Be warned: between this and Restaurant City, you won’t have time for a real job.